Simulation Study on the Effect of Elevated CO2 on Regional Temperature Change on the Loess Plateau

Abstract

CO2 undisputedly affects global temperature change, but the specific impact of change in atmospheric CO2 concentration on regional warming remains to be quantified, especially in different climatic backgrounds. Taking the Loess Plateau as the research area, this study quantified the effect of CO2 elevation on regional temperature change based on a single-factor sensitivity experiment of the regional Weather Research and Forecasting (WRF) climatic model, and the results revealed the following: (i) The correlation coefficient between monthly mean values of temperature simulated by the WRF model and the observed values reached 0.96 (p < 0.01), and the overall spatial trends of simulated and observed temperatures increased from the northwest to the southeast. (ii) CO2 concentration increased from 370.70 ppm in 2000 to 414.54 ppm in 2020, and the Loess Plateau region warmed by 0.04 and 0.06 °C under the MODIS land cover of 2000 and 2020, respectively. This indicates that increase in CO2 concentration over the Loess Plateau has greater impact than land cover change on regional temperature change. (iii) As CO2 concentration increased, the maximum fluctuation of temperature in summer exceeded 2.0 °C, while the fluctuations in spring (0.72 °C), autumn (0.77 °C), and winter (0.15 °C) were relatively small, indicating that summer temperature is most sensitive to CO2 concentration change. By emphasizing the marked temperature difference associated with the same CO2 change in different seasons, this study provides an important basis for extending the understanding of the differences in the effect of CO2 on regional temperatures.